The purpose of the study is to examine the effects of tetrahydrocannabinol on reproductive function in the female monkey. The initial studies will consist of an investigation of the acute and chronic effects of THC on the elevated levels of gonadotrophins in the ovariectomized female monkey. Dose and time course relationships of acute administration of THC: Luteinizing hormone (LH) & follicle stimulating hormone (FSH) levels will be measured by radioimmunoassay at short intervals following administration of a single i.m. dose of THC. The effects of adrenergic drugs and sex steroids on the THC-induced changes in gonadotrophin secretion will also be investigated in an attempt to define the mechanism by which THC affects gonadotrophin secretion. Effects of chronic administration of THC on the gonadotrophin levels: THC will be administered as a single daily dose over a period of days or weeks. Both gonadotrophins will be measured daily and at short intervals following discontinuation of THC administration. The remainder of the study will concern the effects of THC of FSH, LH, estrogen, and progesterone secretion in the normal cycling female monkey. A single dose of THC will be administered at various times during the normal cycle (day 8-28), and hormone levels will be measured at short intervals for the remainder of that cycle. Comparisons will be made between cycles during which THC is administered and those during which vehicle alone is administered. Hormone levels will be monitored for several cycles following the cycle during which the drug is administered (or until a normal cycle is obtained). The chronic effects of THC on the normal cycle will be investigated by administering daily doses of THC during several cycles. Hormones will be measured during these cycles and for several weeks following discontinuation of the THC administration (or until a normal cycle is obtained).